Vehicle AC generator

ABSTRACT

A vehicle AC generator includes a rotor, a stator having a stator core and a stator winding, a pair of front and rear frames and electric components including a rectifier unit and other electrical parts disposed rear of the rear frame. The stator winding is connected to the rectifier unit by one of means of welding, soldering and clamping, and the rear frame has a stay having a fixing surface disposed rear of the electric components. Therefore, it is not necessary to provide a space for screwing a screw bolt to connect the stator winding and the rectifier unit. Because cooling air is discharged from a discharge window along the stay, heated air will not return to any of air intake window.

CROSS REFERENCE TO RELATED APPLICATION

[0001] The present application is based on and claims priority fromJapanese Patent Application 2000-337843, filed Nov. 6, 2000, thecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a vehicle AC generator for apassenger car, a truck or some other vehicles.

[0004] 2. Description of the Related Art

[0005] Recently, the engine compartment has become narrower andnarrower, and there is a limited space for a vehicle AC generator. Inaddition, such a vehicle AC generator is subjected to severer engineheat.

[0006] A conventional vehicle AC generator employs a screw bolt forconnecting a stator winding and a rectifier unit. The screw bolt isfastened by a fastening tool at a portion perpendicular to the axis ofthe AC generator. Therefore, it is necessary, but difficult, to providea space for accommodating such a tool.

SUMMARY OF THE INVENTION

[0007] Therefore, a main object of the invention is to provide animproved vehicle AC generator which can provide a tool space for thescrew bolt in spite of a limited mounting space of the AC generator.

[0008] Another object of the invention is to provide a vehicle ACgenerator that provides efficient cooling performance.

[0009] According to a feature of the invention, a stator winding isconnected to a rectifier unit by one of means of welding, soldering andclamping, and a rear frame has a stay having a fixing surface disposedat the rear of said electric components. Therefore, it is not necessaryto provide a space for screwing a screw bolt to connect the rectifierunit and the stator winding.

[0010] According to another feature of the invention, the stay hasforking link portions, the rear frames has an air discharge windowbetween the link portions, and the rotor has a cooling fan disposed at arear end thereof. Therefore, cooling air is discharged from thedischarge window and guided by the stay, and the discharged cooling airwill not return to any of air intake windows, so that efficient coolingcan be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Other objects, features and characteristics of the presentinvention as well as the functions of related parts of the presentinvention will become clear from a study of the following detaileddescription, the appended claims and the drawings. In the drawings:

[0012]FIG. 1 is a cross-sectional view illustrating a whole structure ofa vehicle AC generator according to a first embodiment of the invention;

[0013]FIG. 2 is a rear view of the vehicle AC generator according to thefirst embodiment;

[0014]FIG. 3 is a perspective view illustrating a pair of conductorsegments forming a stator winding of the AC generator according to thefirst embodiment;

[0015]FIG. 4 is a fragmentary side view of the stator of the vehicle ACgenerator according to the first embodiment;

[0016]FIG. 5 is a fragmentary side view illustrating a connectionportion of an output line of the stator winding and a rectifier unit;

[0017]FIG. 6 is a fragmentary front view illustrating a connectionportion of an output line of the stator winding and a rectifier unit;

[0018]FIG. 7 is a cross-sectional view illustrating a whole structure ofa vehicle AC generator according to a second embodiment of theinvention; and

[0019]FIG. 8 is a perspective view illustrating a variation of theconductor segment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] A vehicle AC generator according to a first embodiment of theinvention is described with reference to FIGS. 1-6.

[0021] As shown in FIG. 1, the vehicle AC generator 1 is comprised of arotor 2, a stator 3, a pair of front and rear frames 4 a and 4 b, arectifier unit 50, a brush unit 51, a voltage regulator 52, a rear cover53, etc.

[0022] The rotor 2 is comprised of an insulated cylindrically woundfield coil 8, a pole core 7 having a plurality of claw poles thatencloses the field coil 8 and a shaft 6 that penetrates the pole core 7and the field coil 8. A mixe-flow flow type cooling fan 11 is welded tothe front end of the pole core 7, and a centrifugal cooling fan 12 iswelded to the rear end of the pole core 7. A pair of slip rings 13 and14 is disposed at a rear portion of the shaft and is connected to thefield coil 8. Electric current is supplied to the field coil 8 from thebrush unit 51 via the pair of slip rings 13 and 14.

[0023] The stator 3 is comprised of a stator core 32, a stator winding31 that is formed from a plurality of conductor segments 33, andinsulators 34 for insulating the conductor segments 33 from the statorcore 32. The stator core 32 is a laminate of thin iron sheets and has aplurality of slots at the inner surface thereof. The insulators 34 aredisposed on the inner wall of the slots.

[0024] The stator winding 31 is comprised of a plurality of conductorsegments 33 connected to each other according to a prescribed rule.

[0025] In FIG. 3, a pair of conductor segments 33 a and 33 b is a baseunit for forming the stator winding 31. Each of the U-shaped conductorsegments 33 has a turn portion 33 c and segment ends 33 e. The turnportion 33 c forms a drive-side or pulley-side coil end 35 together withadjoining inclined portions 33 d. The segment ends 33 e are welded bymeans of TIG (tungsten inert-gas) welding.

[0026] As shown in FIG. 4, each of the conductor segments 33 has a turnportion 33 c disposed at an axial end of the stator core 32 and segmentsends 33 e disposed at the other end of the stator core 32. Coil ends 35a are formed from the inclined portions 33 f that are uniformly disposedboth in an inner layer and an outer layer. Those of the inclinedportions 33 f disposed in the inner layer and those of the inclinedportions 33 f disposed in the outer layer extend in directions oppositeto each other. Coil ends 35 b are also formed from inclined portions 33d that are disposed both in the inner layer and the outer layer. Thoseof inclined portion 33 d disposed in the inner layer and those of theinclined portion 33 d disposed in the outer layer extend in directionsopposite to each other. The pair of front and rear frames 4 a and 4 bsandwiches the stator 3 so that the rotor 2 can be accommodated insidethe stator 3. The rotor 2 is supported so that it can rotate with theshaft 6. Each of the pair of frames 4 a and 4 b has air dischargewindows 42 at portions around the coil ends 35 a or 35 b and air intakewindows 41 at the axial end thereof.

[0027] The front frame 4 a has a front fixing stay 44 and an adjustingstay 45, and the rear frame 4 b has a rear fixing stay 43. The ACgenerator 1 is fixed to a bracket of an engine (not shown) by the frontfixing stay 44 and the rear fixing stay 43.

[0028] The rear fixing stay 43 has a fixing surface 43 a that is to bein contact with the bracket of an engine and located at the rear of therectifier unit 50 and other electric components. The rear fixing stay 43also has a pair of forking link portions 43 b and 43 c that isintegrated with the rear frame 4 b. One of the air discharging windows42 is opened at portion of the rear frame 4 b between the pair of linkportions 43 b and 43 c.

[0029] The rectifier unit 50 rectifies three-phase output power of thestator winding 31 and provides DC power. The stator winding 31 and therectifier unit 50 are connected by means of welding, soldering orclamping.

[0030] As shown in FIGS. 1, 5 and 6, an output line 31 a of the statorwinding 31is extended from a terminal unit 151 of the rectifier unit 50and soldered to a terminal 152. The output line 31 a can be connected tothe terminal 152 by another means, such as welding or clamping, except ascrew bolt. The rear cover 53 is fixed to the rear frame 4 b so as tocover the brush unit 51 and the voltage regulator 52.

[0031] The above-described vehicle AC generator 1 is driven by an enginevia a pulley (not shown). When field current is supplied to the fieldcoil 8, the claw poles of the pole core 7 are excited, and three-phaseAC voltage is generated in the stator winding 31 so that DC power can beprovided at an output terminal of the rectifier unit 50.

[0032] Thus, there is no need to use a screw bolt to connect the outputline 31 a of the stator 3 and the rectifier unit 50. In other words,there is no need to provide any space for screwing a screw bolt.Therefore, the fixing surface 43 a of the rear fixing stay 43 can belocated at the rear of the rectifier unit 50 and other electricalcomponents. Since the fixing surface 43 a is located at the rear of therectifier unit 50 and other components, one of the air dischargingwindows 42 can be located at a portion around the rear coil ends. As aresult, the discharging air is guided by the link portions 43 b and 43 cand the fixing surface 43 a and will not return near any of the airintake windows 41, so that the rectifier unit 50 and other electricalcomponents can be cooled effectively.

[0033] A vehicle AC generator 100 according to a second embodiment ofthe invention is described with reference to FIG. 7. In the meanwhile,the same reference numeral represents the same or substantially the samepart, portion or component, hereafter.

[0034] The AC generator 100 is comprised of a rotor 102, a field coil103, a stator 3, a pair of front and rear frames 104 a and 104 b, arectifier unit 50, a voltage regulator 52, a rear cover 53, etc.

[0035] The rotor 102 is comprised of a shaft 121, a rear pole core 122,a crown-cap-shape front pole core 123, non-magnetic ring 124 that jointsthe rear and front pole cores 122 and 123, a cooling fan 126 welded tothe rear end of the rear pole section 122, etc. The cooling fan 126 iscomprised of a centrifugal fan blades and mixed-flow fan blades, whichare alternately disposed in the circumferential direction.

[0036] The rear pole core 122 is comprised of a boss portion 122 a towhich the shaft 121 is press-fitted, a disk portion 122 b that extendsradially outward from the boss portion 122 a and a plurality of clawpoles 122 c that extends forward in the axial direction from the fringeof the disk portion 122 b. The front pole core 123 is comprised of aring portion 123 b and a plurality of claw poles 123 c that extendsrearward from the ring portion 123 b.

[0037] The claw poles 122 c of the rear pole core 122 c and the clawpoles 123 c of the front pole core 123 are alternately disposed in thecircumferential direction and fixed to each other by the non-magneticring 124.

[0038] The field coil 103 is fixed to the pair of front and rear frames104 a and 104 b by a through bolt 141 and mounted in a portion of afield core 142.

[0039] The pair of front and rear frames 104 a and 104 b sandwiches thestator 3 so that the rotor 102 can be accommodated inside the stator 3.The rotor 102 is supported so that it can rotate with the shaft 121.Each of the pair of frames 104 a and 104 b has air discharge windows 42at portions around the stator winding 31 and air intake windows 41 atthe axial end thereof.

[0040] The front frame 104 a has a front fixing stay 144 and anadjusting stay 145, and the rear frame 104 b has a rear fixing stay 143.The AC generator 100 is fixed to a bracket of an engine (not shown) bythe front fixing stay 144 and the rear fixing stay 143.

[0041] The rear fixing stay 143 has a fixing surface 143 a that is to bein contact with the bracket of an engine and located at the rear of therectifier unit 50 and other electric components. The rear fixing stay143 also has a pair of forking link portions 143 b and 143 c that isintegrated with the rear frame 104 b. One of the air discharging windows42 is opened at portion of the rear frame 104 b between the pair offorking link portions 143 b and 143 c.

[0042] The above-described vehicle AC generator 100 is driven by anengine via a pulley (not shown). When field current is supplied to thefield coil 103, the claw poles 122 c and 123 c of the pole cores 122 and123 are excited, and three-phase AC voltage is generated in the statorwinding 31 so that DC power can be provided at an output terminal of therectifier unit 50. The stator winding 31 and the rectifier unit 50 areconnected by means of welding, soldering or clamping.

[0043] Thus, there is no need to use a screw bolt to connect the outputline of the stator 3 and the rectifier unit 50, and there is no need toprovide any space for screwing a screw bolt. Therefore, the fixingsurface 143 a of the rear fixing stay 43 can be located at the rear ofthe rectifier unit 50 and other electrical components. Since the fixingsurface 143 a is located at the rear of the rectifier unit 50 and othercomponents, one of the air discharging windows 42 can be located at aportion around the rear coil ends 35 b. Therefore, the discharging airis guided by the link portions 43 b and 43 c and the fixing surface 43 aand will not come near any of the air intake windows, so that therectifier unit 50 and other electrical components can be cooledeffectively.

[0044] The conductor segments 33 of the above-described embodiments canbe substituted by conductor segments 341 shown in FIG. 8.

[0045] In the foregoing description of the present invention, theinvention has been disclosed with reference to specific embodimentsthereof. It will, however, be evident that various modifications andchanges may be made to the specific embodiments of the present inventionwithout departing from the scope of the invention as set forth in theappended claims. Accordingly, the description of the present inventionis to be regarded in an illustrative, rather than a restrictive, sense.

What is claimed is:
 1. A vehicle AC generator comprising a rotor, astator having a stator core and a stator winding, a pair of front andrear frames for supporting said rotor and said stator and electriccomponents including a rectifier unit and other parts disposed outsidesaid pair of frames, wherein said stator winding is connected to saidrectifier unit by one of means of welding, soldering and clamping, andsaid rear frame has a stay having a fixing surface disposed at the rearof said electric components.
 2. The vehicle AC generator as claimed inclaim 1, wherein said stay comprises a plurality of link portions, saidpair of front and rear frames has an air discharge window between saidlink portions, said stator winding comprises a plurality of conductorsegments connected to each other at connection portions spaced apartfrom each other in a circumferential direction, and said rotor has acooling fan, disposed at a rear end thereof, for blowing air radiallyoutward.
 3. The vehicle AC generator as claimed in claim 1, wherein saidfield coil is fixed to said pair of front and rear frames, and saidrotor has a plurality of centrifugal fan blades and a plurality ofmixed-flow-type fan blades at the rear end thereof.
 4. A vehicle ACgenerator comprising: a rotor having a cooling fan at a rear endthereof; a stator having a stator core and a stator winding; a pair offront and rear frames for supporting said rotor and said stator, saidrear frame having a plurality of air intake windows at a rear portionthereof; and electrical components including a rectifier unit connectedto said stator winding by one of means of welding, soldering andclamping disposed at the rear of said rear frame; wherein said rearframe comprises a cylindrical outer wall and a fixing stay havingforking link portions extending from said outer wall to a portion rearof said electric components and an air discharging window disposedbetween said forking link portions, and said link portion has a portionfor guiding air discharged from said air discharge window so as not toreturn to any of said plurality of air intake windows.
 5. The vehicle ACgenerator as claimed in claim 4, wherein said stator winding comprises aplurality of conductor segments connected to each other at connectionportions spaced apart from each other in a circumferential direction. 6.The vehicle AC generator as claimed in claim 4, wherein said field coilis fixed to said pair of front and rear frames, and said rotor has aplurality of centrifugal fan blades and a plurality of mixed-flow-typefan blades at the rear end thereof.